DE102021114981A1 - Earphone body with matching openings - Google Patents

Abstract

An earphone body 2 comprises an inner chamber 4, a transducer 6 housed in the inner chamber, a first tuned opening 8 and a second tuned opening 10, the transducer having a front surface 6A and a rear surface 6B, the front Face in the direction of inserting the earphone body when using it. The inner chamber 4 provides a proximal acoustic volume 12 adjacent to the front surface 6A of the transducer and a distal acoustic volume 14 adjacent to the rear surface 6B of the transducer. The first coordinated opening 8 and the second coordinated opening 10 each extend between the distal acoustic volume 14 of the inner chamber 4 and the environment and are configured to provide fluid communication between the distal acoustic volume 14 and the environment. The first tuned aperture 8 is tuned to a first frequency or range of frequencies and the second tuned aperture 12 is tuned to a second frequency or range of frequencies, the first frequency or range of frequencies being lower than that second frequency or the second range of frequencies.

Description

The present disclosure relates to an earphone body with tuned openings. The present invention is applicable to both intra-canal and intra-concha earphones.

Earphones typically come in two forms: closed and open. Closed earphones are intra-canal earphones. As a rule, they are equipped with a tip section that fits snugly into the ear canal of the user and essentially seals off the cavity formed in the ear canal. This way the sound output directly into the ear canal is maximized and lower sound frequencies can be heard. However, other noises are also amplified, such as external vibrations, and these reduce the sound quality for the user. Another disadvantage that can arise with this type of earphone is that the air pressure in the ear canal increases when the tip portion of the earphone is inserted into the ear. This high air pressure can damage the transducer diaphragm and cause discomfort and damage to the user's eardrum, especially at higher sound pressure levels, and further degrade sound quality.

Open earphones can be intra-canal or intraconcha earphones. The intra-canal earphones are similar in design to the closed earphones, but with openings toward the innermost end of the earphone (when in use) to reduce air pressure in the earphone and ear canal. The intraconcha earphones fit into the outer part of the ear and sit just above the ear canal. Since these earphones do not seal the ear canal, sound waves can escape uncontrollably from the earphones and also affect the sound quality. In addition, the acoustic quality is different from user to user due to the variations in ear shapes and sizes.

The present invention aims to provide an improved earphone body to provide optimized and finely tuned adjustment of sound pressure levels over different frequency ranges in use while simplifying the configuration of the earphone body and reducing associated manufacturing costs.

According to a first aspect of the present invention there is provided an earphone body having an inner chamber, a transducer housed in the inner chamber, a first tuned opening, and a second tuned opening, wherein
the transducer has a front surface and a rear surface, the front surface facing in the direction of insertion of the earphone body in use,
the inner chamber provides a proximal acoustic volume adjacent the front surface of the transducer,
the inner chamber provides a distal acoustic volume adjacent to the rear surface of the transducer,
the first coordinated opening and the second coordinated opening each extend between the distal acoustic volume of the inner chamber and the environment and are adapted to provide fluid communication between the distal acoustic volume and the environment, and
the first tuned aperture is tuned to a first frequency or range of frequencies and the second tuned aperture is tuned to a second frequency or range of frequencies, the first frequency or range of frequencies being lower than the second frequency or the second range of frequencies.

The present invention therefore relates to the acoustic type of earphone in which the proximal acoustic volume of the earphone body is designed to be acoustically coupled to the ear entrance of the user. An earphone is to be understood as any in-ear audio device, regardless of whether it is an intra-canal or intra-concha device.

In accordance with the present invention, sound waves from the transducer cause sound pressure in the proximal and distal acoustic volumes of the earphone body. The first coordinated opening and the second coordinated opening are each in fluid communication with the distal acoustic volume of the inner chamber and the environment. The first coordinated opening and the second coordinated opening therefore enable the transmission of sound waves from the distal acoustic volume to the environment. The presence of the tuned openings means that it is easier for the transducer to move air in the inner chamber and this results in better sound quality, especially at low frequencies where the transducer can move a relatively large volume of air when generating sound waves . There may be an overlap in the frequency ranges on which the tuned openings have an effect.

The invention is not limited to the presence of two matched openings; and other openings can also be provided which extend between the distal acoustic volume of the inner chamber and the surroundings or extend between the proximal acoustic volume of the inner chamber and the environment (which may be a user's ear canal).

Each opening can be tailored by selecting an appropriate cross-sectional area and length for the opening. This affects the speed of the air flow during the operation of the transducer and this affects the acoustic reproduction.

Each opening may extend in substantially a single direction (e.g., when the opening is straight) or have one or more changes in direction (e.g., when the opening has a curved section or sections). The first tuned opening and / or the second tuned opening may have a tubular shape that preferably has at least one bent portion along the length of the opening.

The first coordinated opening has at least one dimension (e.g., length, width) that is different from at least one dimension of the second coordinated opening. If further coordinated openings are provided extending between the distal acoustic volume of the inner chamber and the environment, they may have one or more dimensions that are the same as or different from the dimensions of the first and / or second coordinated openings.

The actual dimensions of each opening depend in part on the size of the earphone body and, more particularly, the distal acoustic volume of the inner chamber of the earphone body.

The first tuned opening may have a smaller width to length ratio than that of the second tuned opening.

The first tuned opening may have a smaller cross-sectional area to length ratio than that of the second tuned opening.

The first coordinated opening provides an acoustic volume that is preferably different from the acoustic volume provided by the second coordinated opening. If further coordinated openings are provided which extend between the distal acoustic volume of the inner chamber and the surroundings, they can each provide an acoustic volume which corresponds to or differs from the acoustic volume of the first and / or the second coordinated opening.

The first coordinated opening and the second coordinated opening preferably have different cross-sectional areas in a direction perpendicular to each of their lengths: the lengths of these openings can be the same or different, with different lengths being preferred. It is also conceivable that the first coordinated opening and the second coordinated opening have the same cross-sectional area but different lengths.

The cross-sectional area of each opening is preferably uniform over the entire length of the opening, but this is not essential.

In one embodiment, at least one opening is substantially circular in cross section in a direction perpendicular to its length. When the first coordinated opening and the second coordinated opening are both circular in cross section in a direction perpendicular to their length, the first coordinated opening has a diameter that is preferably different from the diameter of the second coordinated opening.

The presence of the first coordinated opening and the second coordinated opening help control the pressure sound level over different frequency ranges for the user.

Preferably, the first tuned aperture is tuned to a low frequency or a range of low frequencies and the second tuned aperture is tuned to either a low frequency or a range of low frequencies or to a medium frequency or a range of medium frequencies. In one embodiment, the first tuned opening is tuned to a significantly lower frequency or a significantly lower frequency range than the second tuned opening.

The openings are provided to modify the frequency response of the earphone by tuning the frequency response. The first matched aperture and the second matched aperture are preferably calibrated to achieve a desired acoustic response, such as enhancing bass response.

In general, the larger the acoustic volume of a tuned opening according to the present invention, the lower the acoustic resistance within the distal acoustic volume: this increases the acoustic response.

By designing each matched opening to predetermined dimensions, a corresponding acoustic mass results. The acoustic mass is the effect of the movement of Sound waves affect the air mass in the opening and is dependent on the cross-sectional area of the opening in a direction perpendicular to its length, the length of the opening and the density of the air in the opening.

A combination of the acoustic mass and the distal acoustic volume of the inner chamber acts like a Helmholtz resonator at certain frequencies: This combination of the acoustic mass and the distal acoustic volume can be designed to amplify lower frequency sounds and / or the sound pressure level for one Control user.

The frequency or range of frequencies to which each aperture is tuned is a tuning frequency or range of tuning frequencies, and tuning frequency refers to the dip in the frequency response produced by the aperture due to Helmholtz resonance generated in conjunction with the distal acoustic volume of the inner chamber.

worin: fv die Resonanzfrequenz des Resonators ist (Hz), V das Volumen der Resonanzkammer ist (mm³), D der Durchmesser des Schallabgabelochs ist (mm), L die Tiefe des Schallabgabelochs ist (mm) und C die Schallgeschwindigkeit ist = ca. 344000 (mm/s).The following formula relates to the resonance frequency of a resonator which has a single opening (sound emission hole) that is circular in cross section and an acoustic volume (volume of the resonance chamber) which, in the case of the present invention, is the distal acoustic volume of the inner chamber of the Earphone body is. $$\text{fv}=\frac{\text{CD}}{\mathrm{4th}}\sqrt{\frac{1}{\mathrm{\pi }\text{V}\left(\text{L.}+0.75\text{D.}\right)}}$$

where: fv is the resonance frequency of the resonator (Hz), V is the volume of the resonance chamber (mm ³ ), D is the diameter of the sound emission hole (mm), L is the depth of the sound emission hole (mm) and C is the speed of sound = approx. 344000 (mm / s).

Assuming that the volume of the resonance chamber is fixed, the relevant parameters are the cross-sectional area of the opening and the length of the opening. For openings that are circular in cross-section, the cross-sectional area is defined by the diameter according to this formula. An opening that is not circular in cross-section but has the same cross-sectional area as an opening of the same length that is circular in cross-section has essentially the same system resonance frequency, provided the same distal acoustic volume holds, so this formula applies to Openings that are not circular in cross section is a good approximation. For example, the matched openings can have an oval or polygonal shape (e.g., rectangular, pentagonal, hexagonal) in cross-section. The cross-sectional shape of the first coordinated opening may differ from that of the second coordinated opening.

In accordance with the present invention, providing two openings that are tuned to different frequencies and balancing the acoustic resistance in those openings enables finer control over the shape of the frequency response.

The first tuned aperture is preferably tuned to a frequency or range of frequencies that is significantly lower than the frequency or range of frequencies of the second tuned aperture, e.g., on the order of two.

By controlling additional acoustic resistances in the system, the relative contribution of the matched openings to the overall frequency response enables the system frequency response to be matched.

In one embodiment, the sound pressure level is increased or decreased by providing an amount of acoustic resistance to the first coordinated opening and / or the second coordinated opening. Preferably one or more acoustic resistance means are provided in series with the acoustic ground of the or each matched opening. These acoustic resistors can be in the form of a mesh fabric with an acoustic resistance value. The sound pressure level can be increased or decreased through the use of acoustic resistance means over predetermined frequency ranges.

The first and / or second mated openings of the present invention can be positioned so that they are substantially opposite the rear surface of the transducer.

In one embodiment, the first and / or second mated openings are located in a rear portion of the earphone body, e.g., in a back wall of the earphone body.

The location of each tuned aperture is of relatively little concern provided the apertures of the apertures are not blocked or too close to other components in the internal chamber of the earphone body. This is due to the fact that the wavelengths in question are significantly larger than the dimensions of typical earphones.

A front portion (eg, a front wall) of the earphone body is provided with at least one acoustic opening to allow sound to exit from the proximal acoustic volume to be received by the user's ear. This acoustic opening can be substantially opposite the front surface of the transducer.

According to a second aspect of the present invention there is provided an earphone comprising the earphone body of the present invention. The earphone can be configured to communicate with other devices such as smartphones, tablets or laptops; this communication can be wireless or wired.

According to a third aspect of the present invention there is provided a method of adjusting sound pressure levels emitted from an earphone to a user's ear using the earphone body of the present invention, the method comprising: sending an electrical signal to the transducer to Generate sound waves in the proximal and distal acoustic volumes in the inner chamber of the earphone body; Outputting the sound waves to be received by an ear of the user (i.e. from at least the proximal acoustic volume); and transmitting sound waves from the distal acoustic volume to the environment through the first coordinated opening and the second coordinated opening.

• 1 ist eine schematische Darstellung eines Ohrhörerkörpers gemäß einer Ausführungsform der vorliegenden Erfindung;
• 2 ist eine perspektivische Ansicht der Oberseite eines Teils eines Ohrhörerkörpers mit einem Abschnittsausschnitt, um Querschnitte einer ersten abgestimmten Öffnung und einer zweiten abgestimmten Öffnung in Richtung ihrer Länge zu zeigen;
• 3 ist ein Diagramm von Schalldruckpegel (SPL) (y-Achse) in Abhängigkeit von der Frequenz (Hertz) (x-Achse) für eine abgestimmte Öffnung für tiefe Frequenzen; und
• 4 ist ein Diagramm von Schalldruckpegel (SPL) (y-Achse) in Abhängigkeit von der Frequenz (Hertz) (x-Achse) für eine abgestimmte Öffnung für mittlere Frequenzen.

Non-limiting embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings.

• 1 Figure 3 is a schematic illustration of an earphone body in accordance with an embodiment of the present invention;
• 2 Fig. 13 is a perspective view of the top of a portion of an earphone body with a section cut out to show cross sections of a first mated opening and a second mated opening in the direction of their length;
• 3 Figure 13 is a graph of sound pressure level (SPL) (y-axis) versus frequency (Hertz) (x-axis) for a tuned opening for low frequencies; and
• 4th Figure 13 is a graph of sound pressure level (SPL) (y-axis) versus frequency (Hertz) (x-axis) for a tuned aperture for medium frequencies.

With reference to 1 exhibits an earphone body 2 an inner chamber 4th , a converter 6th housed in the inner chamber has a first tuned port 8th and a second coordinated opening 10 on. The earphone body can be used for closed or open type earphones. The earphones can be intra-canal or intraconcha earphones as required.

The converter 6th has a front face 6A and a rear face 6B with the front surface facing in the direction of insertion of the earphone body into the entrance of an ear of a user when the earphone is in use. The converter 6th can be of any type suitable for use in an earphone, and is typically a driver (e.g., a speaker for receiving electrical signals). The converter 6th is coupled to and operated by one or more electronic devices (not shown).

The inner chamber provides a proximal acoustic volume 12th adjacent to the front surface 6A of the converter ready. The inner chamber also provides a distal acoustic volume 14th adjacent to the posterior surface 6B of the converter ready.

The first coordinated opening 8th and the second matched aperture 10 each extend between the distal acoustic volume 14th the inner chamber 4th and the environment and are configured to provide fluid communication between the distal acoustic volume 14th and the environment.

In this embodiment, the first are matched openings 8th and the second matched aperture 10 in a rear section 16 (For example a back wall) of the earphone body is arranged, which in this example is essentially the rear surface 6B of the converter are opposite. A front section 18th (e.g. a front wall) of the earphone body is with a primary acoustic opening 20th which allows the sound to exit the proximal acoustic volume and enter the user's ear canal. In this example, this acoustic opening is essentially the front surface 6A of the converter opposite.

The earphone body 2 can either be the outer housing of an earphone or a separate component within an earphone. The earphone body is designed to receive digital or analog audio data to output the audio to a user. The earphone body 2 can be formed from a rigid material such as plastic. In its inner cavity 4th there are internal components such as the converter 6th , and the earphone body is designed to protect it from damage.

Referring to the 1 and 2 assign the first matched opening 8th and the second matched aperture 10 a circular cross-section in a direction perpendicular to the length of each Opening up. Alternatively, the first matched opening 8th and the second matched aperture 10 have a non-circular cross-sectional shape in a direction perpendicular to their lengths; for example, the matched openings can have an oval or polygonal shape (eg rectangular, pentagonal, hexagonal) in cross section. The cross-sectional shape of the first coordinated opening in a direction perpendicular to its length may also differ from the cross-sectional shape of the second coordinated opening in a direction perpendicular to its length.

Each opening of this embodiment is tailored by selecting an appropriate length and diameter (and thus a suitable cross-sectional area) for the opening. As in 2 shown, there is the first coordinated opening 8th of two straight sections along their length that meet at an angle between 100 and 150 degrees. The second coordinated opening 10 also consists of two straight sections along its length that meet at an angle of about 90 degrees. However, one or both of the coordinated openings can also consist of a single straight section or of three or more straight sections. Alternatively, one or both of the matched openings can consist of one or more curved and / or straight sections. The portions of each opening are in fluid communication with one another.

It can be seen that the length and diameter of the first matched opening 8th on the length and diameter of the second matched opening 10 differ in the present embodiment.

Each opening is matched to a specific frequency response, in particular by selecting a suitable cross-sectional area and length for the opening. The dimensions of the first matched orifice and the second matched orifice are calibrated to provide different frequency responses, with the first matched orifice being tuned to a lower frequency or range of frequencies than the second matched orifice.

The ratio of cross-sectional area to length defines the tuning frequency for a given fixed distal volume. A smaller ratio results in an opening that is tuned to lower frequencies.

Referring to the 1 and 2 the second tuned opening has a larger cross-sectional area and a shorter length than the first tuned opening. The first coordinated opening therefore has a lower diameter to length ratio than the second coordinated opening, along with a lower cross-sectional area to length ratio than the second coordinated opening.

The first coordinated opening 8th can be tuned to a low frequency or a low range of frequencies, for example frequencies between 50 Hz and 800 Hz. The second tuned aperture 10 can be tuned to a medium frequency or a medium range of frequencies, for example frequencies between 800 Hz and 4 kHz. The first matched opening and the second matched opening can be tuned to different or overlapping frequency ranges.

As an example only, a representative length for the first matched opening is 5 mm and a representative diameter for the first matched opening is 1 mm. The ratio of diameter to length for the first matched opening in this example is therefore 1: 5 and the ratio of cross-sectional area to length for the first matched opening in this example is 79: 500. Assuming a distal acoustic volume of around 1 cm ³ , this results in a tuning frequency of around 650 Hz.

As an example only, a representative length for the second matched opening is 2 mm and a representative diameter for the second matched opening is 1.5 mm. The ratio of diameter to length for the second tuned opening in this example is therefore 3: 4 and the ratio of cross-sectional area to length for the second tuned opening in this example is 177: 200. Assuming a distal acoustic volume of around 1 cm ³ , the result is a tuning frequency of around 1300 Hz.

The sound pressure level in the earphone body can be increased or decreased by providing an amount of acoustic resistance to the first matched port and / or the second matched port. In one embodiment, one or more forms of acoustic resistance are provided in series with the acoustic mass of the first matched opening and / or the second matched opening. Acoustic resistance refers to the energy loss of a sound wave and so providing an acoustic resistance means in series with the acoustic mass reduces the energy of a sound wave.

The acoustic resistance means can be in the form of an acoustic mesh fabric. The acoustic resistance means can be placed over at least one opening of one or both of the matched openings. Alternatively or additionally, the acoustic resistance means can be placed inside one or both of the matched openings. The mesh fabric can be attached, for example, by glue, rubbing or snapping. It will be understood that other forms of acoustic resistance means can be used in addition or as an alternative. An acoustic resistance means has an associated resistance value that can be expressed in Rayleigh, where 1 Rayleigh (1 Rayl) is equal to 1 Pascal-second per meter.

By compensating for factors such as acoustic resistance, the frequency response for frequencies in the middle range and frequencies in the low or low range (e.g. bass frequencies) can be optimized for the correspondingly adjusted opening.

the 3 and 4th are diagrams of sound pressure level (SPL) as a function of frequency (Hertz), the diagram of 3 relates to the effect of varying degrees of acoustic resistance on a first tuned aperture tuned to lower (low) frequencies, and 4th relates to the effect of varying degrees of acoustic resistance on a second tuned aperture that is tuned to higher (medium) frequencies.

The diagrams of these figures were created using a computer simulation. The system with two openings was also measured on real samples, but the simulation allows a more detailed variation of the acoustic resistance parameters for a better visual representation.

As in 3 As shown, increasing the amount of acoustic resistance leads to a decrease in sound pressure at the lower frequencies.

Referring to 4th conversely, with increasing acoustic resistance there are higher sound pressure levels at higher frequencies, so that a lower acoustic resistance for the second matched opening 10 may be preferred in order to enable an amplification of the frequencies in the middle range.

The earphone and the earphone body of the present invention may contain other components, including a battery, a transceiver, a micro-USB charging terminal, a capacitor, a Bluetooth ^® module, a magnet and a microphone, but are not limited thereto. The internal components of the earphone and earphone body can be arranged in any configuration that provides adequate, preferably optimal, acoustic performance.

The tuned openings of the present invention are not holes or openings for microphones or sensors.

The invention has been described above with reference to a specific embodiment, which serves only as an example. It will be understood that various configurations are possible which fall within the scope of the appended claims.

Claims (12)

An earphone body having an inner chamber, a transducer housed in the inner chamber, a first tuned opening and a second tuned opening, wherein the transducer has a front surface and a rear surface, the front surface facing in the direction of insertion of the earphone body in use, the inner chamber provides a proximal acoustic volume adjacent the front surface of the transducer, the inner chamber provides a distal acoustic volume adjacent to the rear surface of the transducer, the first coordinated opening and the second coordinated opening each extend between the distal acoustic volume of the inner chamber and the environment and are adapted to provide fluid communication between the distal acoustic volume and the environment, and the first tuned aperture is tuned to a first frequency or range of frequencies and the second tuned aperture is tuned to a second frequency or range of frequencies, the first frequency or range of frequencies being lower than the second frequency or the second range of frequencies. Earphone body as in Claim 1 claimed, wherein the first tuned opening has a lower ratio of cross-sectional area to length than the second tuned opening. Earphone body as in Claim 1 or Claim 2 claimed, wherein the first tuned opening has at least one dimension that is different from the dimension of the second tuned opening, the dimension selected from the group consisting of width, diameter, length and cross-sectional area in a direction perpendicular to the length. Earphone body as in Claim 3 claimed, the first matched opening and / or the second tuned opening is substantially circular in cross section in a direction perpendicular to the length of the tuned opening. An earphone body as claimed in any preceding claim, wherein the first tuned opening and / or the second tuned opening is tubular. Earphone body as in Claim 5 claimed, wherein the first coordinated opening and / or the second coordinated opening is tubular in shape with at least one bent portion along the length of the opening. An earphone body as claimed in any preceding claim, wherein the first tuned opening and / or the second tuned opening are arranged to substantially oppose the rear surface of the transducer. An earphone body as claimed in any preceding claim, wherein the first tuned opening and / or the second tuned opening are located in a rear portion of the earphone body. An earphone body as claimed in any preceding claim, wherein the first tuned opening and / or the second tuned opening is provided with at least one acoustic resistance means. Earphone body Claim 9 wherein the acoustic resistance means comprises a mesh fabric. An earphone comprising the earphone body of any preceding claim. A method of adjusting sound pressure levels output from an earphone to a user's ear using the earphone body of any preceding claim, the method comprising: Sending an electrical signal to the transducer to generate sound waves in the proximal and distal acoustic volumes in the inner chamber of the earphone body; Outputting the sound waves intended to be received by a user's ear; and Transmitting sound waves from the distal acoustic volume to the environment through the first coordinated opening and the second coordinated opening.

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